The present invention relates to an apparatus and a method for testing the performance of a railroad vehicle or an automobile and, more specifically, to an apparatus and a method for testing a truck of a railroad vehicle or a suspension of an automobile.
Since the truck of a railroad vehicle and the suspension of an automobile are important parts that determine the degree of comfortability of a ride in the vehicle and the stability during running, it is necessary to evaluate the performance of the truck or suspension before the development of a vehicle. In particular, there is a possibility that a truck may make a snake action during high-speed running. It is an important subject to avoid the snake action.
At present, tests are conducted by using an actual truck to clarify how the phenomenon of snake action occurs during running of a vehicle, because it is difficult to analyze the snake action by computer simulation mainly for the following reasons:
(1) It is difficult to analyze the contact surfaces between the wheels and the rails. PA1 (2) Trucks have many structure-related nonlinear factors.
Among the tests using an actual truck is what is called an actual vehicle test in which an actual vehicle is run on actual rails. On the other hand, an on-base test is also conducted in which a truck is mounted on rail wheels. In the on-base test, a plurality of wheels are rotatably joined to the bottom portion of a truck and a weight frame having a weight corresponding to that of a vehicle is mounted on the top-surface side of the truck. The wheels, the truck, and the weight frame simulate a railroad vehicle. On the other hand, to simulate railroad rails of infinite length, a plurality of cylindrical rollers are rotatably provided on a base. The wheels provided at the bottom of the truck and the cylindrical rollers are located at positions that correspond to each other. The running characteristics of the railroad vehicle on rails can be simulated by mounting a mock vehicle on the rollers and rotating the rollers with one end of the truck fixed to a coupler. An example of such a testing apparatus is described in Hirotsu et al., "Simulation of Snake Action of Railroad Vehicles," Transactions of the Japan Society of Mechanical Engineers, Vol. 532 Ed. C, No. 90-0204A, pp. 65-72, December 1990.
However, in the above conventional actual vehicle test, the results of each test is are results obtained one combination of conditions (such as a vehicle structure, rail states, and running conditions). Since the actual vehicle test involves a number of parameters, it is difficult to determine the running performance and the degree of comfortability of a ride under another combination of conditions based on the experimental results obtained. In the on-base test, since the mock vehicle is bound by the coupler, relative positions of a vehicle in the running direction are determined in accordance with whether the wheels are rotating in the normal or reverse direction. However, in this case, it is difficult to take the characteristics of the vehicle into account, and the motion of the mock vehicle is different from that of an actual vehicle. Therefore, satisfactory test results cannot be obtained. Further, trucks having an active damper that have been developed in recent years require that a movement state be fed back as a feedback signal. Therefore, there is a problem that the on-base test cannot accommodate such trucks.